1. Field of the Invention
The present invention refers to an apparatus for the preparation of hot beverages, especially of coffee. Particularly the invention refers to the so-called "Espresso"-machines, which are used more and more in households and which allow to prepare an unlimited number of cups of fresh coffee, one after the other one. Still more particularly, the inventions refers to a coffee machine which includes a housing, a fresh water inlet or a fresh water supply reservoir, a heating means adapted to heat the fresh water, an installation to supply the heated fresh water to a brewing chamber under pressure, said brewing chamber comprising a closure means and an inlet for beverage powder as well as an outlet for beverage, and further including, if appropriate, an installation for pushing out and removing, respectively, the leached-out beverage powder out of the brewing chamber and from the brewing chamber, respectively, as well as including driving and control means for the said installations and means.
2. Prior Art
Such apparatus exist in a wide variety on the market and have a widespread use in households. Similar apparatus having basically the same design are also used commercially, e.g., in restaurants, in canteens and so on. The essential difference between machines for household use and commercially used ones may be seen in the fact, that the dosage and the feed of the coffee powder prior to the preparation of the beverage as well as the removal of the leached-out coffee powder after the preparation of the beverage is performed more or less automatically in the case of commercially used machines. In this way the preparation of the beverage may be performed quicker and thereby with more efficiency.
A fundamental disadvantage, common to both the apparatus used in the houshold as well as the commercially used ones, may be seen in the fact that certain parts of the apparatus are subject to contamination. This is particularly true for those parts of the apparatus which are contacted, on the one hand, by the coffee powder, especially during the brewing of the beverage, and, on the other hand, by the prepared beverage. In the interest of impeccable hygienic conditions it will be necessary to clean the said parts from time to time. While such cleaning procedure involves but some inconvenience and additional work as far as household apparatus are concerned, the operational interruptions during the cleaning process in the case of commercially used apparatus are much more serious and have to be considered. Known apparatus of the commercial kind have to be put completely out of operation and should preferably be disconnected from the mains supply while the contaminated parts are thouroughly cleaned. In most cases the apparatus has to be switched off a certain period in advance in order to enable the parts to be cleaned to cool down at least to a certain degree. The cleaning procedure having been completed, a considerable period of time is required until the apparatus is ready for further use.